I haven’t discovered this myself yet but I’m eager to try it out. There is a very odd moment in Pokemon X/Y when the player goes to the second floor the dojo building in Luminose City.
Watch what happens here. Sorry for the bad quality video.
The player’s character enters the room and the lights flicker. Suddenly a mysterious girl appears all Ju-On style and floats forward without doing a walking animation like a real creep. She then tells the player that they aren’t “the one.” Apparently this girl may have appeared in Pokemon Black and White though I wasn’t aware of her presence in those games.
What the heck could this be? Hopefully someone will discover soon.